Friday 25 September 2009 09.07 EDT
First published on Friday 25 September 2009 09.07 EDT

Sir Richard Dalton, former UK ambassador to Iran

"Iran seems to have been tipped off and come clean because it knew it was about to be rumbled. People have always thought that the most likely route to getting nukes was through a covert facility. So my first reaction is relief: a covert plant has been discovered. Does that reduce the risk of Iran still being able to cheat? It shifts the odds in favour of the P5 [five permanent members of the UN security council]. It looks like what happened with Libya in 2003 when they were rumbled and were told 'there is a fork in the road.' It's vital to know what's in the plant – the detail is crucial. What's it a pilot project for? There's no benign interpretation of this. But the Iranians may say: 'What do you expect? You've been threatening to bomb Natanz, so why should we tell you about this?'"

Mark Fitzpatrick, International Institute of Strategic Studies, London

"This is not a smoking gun in that it is not known that the plant was intended for military purposes, but one could suspect that it might be, given that it was hidden. It's akin to how they were caught cheating in 2002. It increases suspicions and leads one to wonder what else they have hidden. This plant could have been a replacement for Natanz if that was bombed or it could just be part of expanding facilities. It validates what the US, UK and others have been saying – even though it's not clear whether Iran intended it for civilian or military purposes."

Gala Riani, Middle East analyst, IHS Global Insight

"It's a bombshell. The timing of this is fascinating. It strengthens the hands of the US and its allies and shows they will push for tougher sanctions. It raises significant suspicions that Iran may have other clandestine nuclear facilities as well as questions about the timing of its break–out capacity. It is more damaging to Iran than the Natanz revelation was in 2002 because now there is a sense that time is running out."

Meir Javedanfar, Israeli expert on Iran

"It is a vindication for Israel and supports Israel's position for the last 10 years that Iran is not being frank and honest in its dealings with the International Atomic Energy Agency. If people are going to talk to Iran I think there will be more room for Israel's assessment of the situation."